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CodeWarrior C
有时候在程序中会出现
EnableInterrrupt；
ClearReg0
我们看字面意思很容易懂它是什么意思，但是一般初学者一般会被它搞晕，为什么就这样一个单词就能表示开中断呢，其实它在头文件中时有定义的，那就是宏定义，这个单词代表的是一些语句，在包含文件里面有定义的，就是方便编程，增加程序的可读性，下面是CodeWarrior 宏定义的解释：
Defining a Macro
An HLI assembler macro is defined using the preprocessor directive `define'.
Example:
/* Following macro clears the register zero. */
#define ClearReg0 {asm CLR Reg0;}
The macro is invoked in the following way in the source code:
ClearReg0;
The preprocessor expands the macro:
{asm CLR Reg0;};
Example:
/* Following macro clears the registers 0 and 1. */
#define ClearReg0And1 {asm CLR Reg0; asm CLR Reg1}
The macro is invoked in the following way in the source code:
ClearReg0And1;
The preprocessor expands the macro:
{asm CLR Reg0; asm CLR Reg1; };
You can define an HLI assembler macro on several lines using the line separator `\'.
Example:
/* Following macro clears the registers 0 and 1. */
#define ClearR0andR1 {asm CLR Reg0; \
asm CLR Reg1}
The macro is invoked in the following way in the source code:
ClearR0andR1;
The preprocessor expands the macro:
{asm CLR Reg0; asm CLR Reg1; };
Using Macro Parameters
An HLI assembler macro may have some parameters which are referenced in the macro code.
Example:
/* This macro initializes the specified variable to 0.*/
#define Clear(var) {asm CLR var}
The macro is invoked in the following way in the source code:
Clear(var1);
The preprocessor expands the macro:
{asm CLR var1 ; };
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